Wide angle surface generator &amp; target

ABSTRACT

An axicon is disclosed comprising a generally cylindrical body having an exterior surface  31 , a first surface  32  and a second surface  35  adjacent opposite ends of the body. A light input beam from a suitable source is directed into one of those surfaces and through the axicon to the other of those surfaces, and the beam is transformed by the axicon into a beam(s) exiting such other surface. The shape and angular extent of the exit beam will depend, in part, on the selected position of the first surface with respect to the optical axis of the axicon and/or the second surface. The axicon is an optical grade unit, preferably unitary, which can receive light of a specified pattern through a first surface, redirect and modify the light, and output light of a different pattern though a second surface. A concentrated light beam can be input to the axicon and output as a differently shaped beam, such as defining a predetermined plane or geometric surface., Also light surrounding the axicon can be input, concentrated and output as a beam of predetermined size and shape onto a photodiode supported at or near the focal point of the lens.

FIELD OF THE INVENTION

[0001] This invention relates to simplified optical devices for the generation of optically visible reference patterns and also as target devices which are useful for alignment and guidance purposes, especially in cooperation with photosensitive units (e.g photocells, photodiodes, etc.) and related electronics.

SUMMARY OF THE INVENTION

[0002] Several embodiments of the invention are disclosed, which are unique optical members, hereinafter called axicons, which accept an input beam, such as from a laser light source, and transform and output that beam as a fan shaped beam of coherent light directed along a desired plane or other surface shape. These optical members (axicons) can also be adapted to use as targets receiving omnidirectional light input over relatively wide angles, e.g. 180° to 360°, preferably in combination with photodiodes or the like which are sensitive to intensity of light rays directed (output) onto them by the targets.

[0003] The optical members are elongated optical grade units comprising a specially formed axicon which can receive light of a specified pattern through a first surface, redirect and modify the light, and output light of a different pattern though a second surface. For example, a concentrated light beam can be input to the axicon and output as a differently shaped beam, such as along a predetermined plane, or light surrounding the axicon can be input, concentrated and output as a beam of predetermined size and shape onto a photodiode supported at or near the focal point of the lens. The optical members are preferably unitary, and have the axicon and lens configurations formed onto or in them, but they may be provided and utilized as a matched pair.

[0004] The photodiodes (or equivalent) in the second configuration can be used to provide a signal which is proportional to the quantity of illumination to which they are subjected, and appropriate per-se known circuitry may be used to determine thresholds for minimum and/or maximum light input intensity.

[0005] In the first configuration, the shaped beam (for example fan shaped) can be used for a number of different alignment purposes.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006]FIGS. 1, 2 and 3 are, respectively, side views of optical target axicons illustrating the use of the invention to transform an input beam into a shaped beam of predetermined size and configuration

[0007]FIGS. 4, 5 and 6 are side views similar to FIGS. 1, 2 and 3, illustrating the use of the invention to transform surrounding light patterns, e.g. a fan shaped beam, into a focused beam;

[0008]FIG. 7 is a top view of the axicon shown in FIG. 3, with ray direction lines superimposed thereon;

[0009]FIG. 8 is a perspective view of the axicon shown in FIG. 6, with ray direction lines superimposed;

[0010]FIG. 9 is a perspective view of a dual optical target instrument according to the invention, supported in a generally U-shaped body, which redirects incoming light from a major portion of the sides of the optical target members onto a pair of spaced apart photo sensors;

[0011]FIG. 10 is a front view of the instrument shown in FIG. 9;

[0012]FIG. 11 is a side view of the instrument shown in FIG. 9;

[0013]FIG. 12 is a rear view of the instrument shown in FIG. 9.

[0014] Description of the Various Embodiments

[0015] An axicon constructed according to the invention is shown in FIGS. 1-8, as comprising a generally cylindrical body having an outer surface 31, a first surface 32 and a second surface 35. A light input beam from a suitable source is directed into one of those surfaces and through the axicon to the other of those surfaces, and the beam is transformed by the axicon into a beam(s) exiting such other surface. The shape and angular extent of the exit beam will depend, in part, on the selected position of the first surface with respect to the optical axis of the axicon and/or the second surface.

[0016] In one example of a configuration the shaped exit beam can be used (for example) as a reference defining a plane and can be detected, for example, by passing a photodiode through the exit beam 45. Multiples of these units can be used, for example, to define otherwise invisible boundaries or limits within a predetermined space (see FIGS. 9-12). In another configuration light rays from the sides of the axicon can enter the axicon as an input and be shaped to a defined beam directed as an output on a photodetector or the like.

[0017] Referring to FIGS. 1, 2 and 3, a configuration of the invention comprises a axicon body with an outer surface 31, a first suface on the body which is a lens surface 32, and the second surface on the body, which is a conic surface 35. Here, an input beam 40, typically a laser beam generated by a laser diode, is directed into and along the axicon, entering at first surface 32 and along the axicon to the conic surface 35, and the beam is transformed by the axicon into beams 42 exiting outward from conic surface 35. The width and angular extent of the exit beam will depend on the selected position of the conic surface 35 with respect to the optical axis of first surface 32 and/or the optical axis of the axicon body itself, as illustrated respectively in FIGS. 1, 2 and 3.

[0018] Referring to FIGS. 4, 5, and 6, other configurations and forms of axicons are shown as incorporating a cylindrical body (by way of example) which has an outer side surface 31 of predetermined shape (in this case a right cylinder), surface lens 32 adjacent one of its ends, and a biconic surface lens 35 at the other end. The conic (or partially conic) surface 35 is formed as a segment of a cone extending across or partially across the opposite end of the body, i.e. opposite lens 32.

[0019] In FIG. 4 the conic surface 35 (which in this case is the input) is coaxial with lens surface 32 (which is the output) and with the axis of the axicon body. In FIG. 6, the conic surface 35 is offset with respect to the optical axis of output lens 32. In FIG. 7, the apex of the conic surface 35 is coincident with or outside the side surface of the axicon.

[0020] In each case, the curvature of surface 35 is chosen such that it redirects light from a beam impinged on the outer surface of the body opposite the conic segment surface 35. Thus the surfaces 32 and 35 together function as an axicon which redirects rays from a beam or beams incoming from entirely or partially around surface 31, opposite from and onto surface 35. The different locations of the conic surfaces, shown in FIGS. 5, 6, and 7, will dictate the extent of the angle of acceptance of an input beam 36 about the surface 31. This configuration can be used to direct the exiting concentrated light from lens 32 onto a photo sensor, and utilized in the same general manner as described above.

[0021]FIGS. 7 and 8 are top and isometric views, respectively, of the axicons as shown in FIGS. 3 and 6. These figures show ray lines in FIG. 7 to illustrate the acceptance angle of the axicon, and a wire frame illustration in FIG. 8 of the conic surfaces 35 in FIGS. 3 and 6.

[0022] All of the above described unique axicons can be constructed as integral units in their final configuration. They can be manufactured from a single bar or block of optical grade material, or molded as a single unit, or can be formed of input and output sections, preferably joined (rather than mounted) together. The axicons are passive devices which require a minimum of adjustment in performing the various beam transformations described above, and are capable of functioning with quite low levels of energy. It should also be noted that the receiving surface 32 in a configuration could be simply a precisely formed planar surface, and not technically a lens.

[0023] Referring to FIGS. 9 through 12, an optical target instrument is shown which is essentially omnidirectional in input sensitivity. For purposes of explanation, it will be assumed that a reference beam, preferably of coherent light (e.g. a laser beam) is directed along a path indicated by arrow B. Thus, in each part of the dual optical unit shown in FIGS. 9-12, the cylindrical outer surface 14 and the conical interior surface 20, plus the first outer surface (lens surface) 22, function as an axicon which redirects light rays received by the outer surface 15 into the lens 22 which concentrates and transforms them at the end of the body 10 opposite the conical surface.

[0024] The beam B can impinge on the dual optical unit 10 which is comprised of like units 12 and 14 attached in vertically opposed relation such that the cylindrical outer side surfaces 15 of the joined units function as the input surface of the optical unit, and the center of the dual optical unit is at their joint. In this embodiment, internally of the units there are conical surfaces 20 which have their axes coincident with the axis of the outer surfaces 15 and which function to redirect light rays

[0025] It should be understood that a single one of the dual unit axicons 10 has utility of its own, but the joined pair are illustrated by way of explanation of an updown control instrument. This instrument comprises a generally U-shaped body 25 with forward projecting arms 26 and 28 which support photo sensors 30A and 30B. The main portion of the body is hollow and is a convenient housing for a portable power source and circuitry which is connected to the photo sensors or other associated electronic equipment.

[0026] The dual optical unit is supported between the arms 26, 28. In the illustrated orientation this unit is vertically supported. Lenses 22 serve to concentrate the light reflected from conical surfaces 20 onto upper and lower photo sensors 30A, 30B. When the input beam is centered on the joint of the two optical units, at the bases of the respective conical surfaces, the quantity of light directed to the two photo sensors is equal, i.e. the beam is equally divided. If the beam center is above or below the center, a greater quantity of light will be directed to the upper or lower photo sensor, as the case may be. Thus, the signal output of the photo sensors will be differential with respect the the amount of displacement of the center of the dual optical unit from the beam centerline.

[0027] With the instrument body 25 oriented horizontally, the instrument can be used to detect lateral displacement with respect to the beam centerline. The respective optical units are capable of omni-directional sensitivity to beams directed against any part of their side surface, and appropriate changes in the mounting of a single or dual optical unit can be provided to achieve a desired result.

[0028] While the described articles and apparatus constitute preferred embodiments of this invention, the invention is not limited to these precise articles, and forms of apparatus, and that changes may be made in either without departing from the scope of the invention defined in the appended claims. 

What is claimed is:
 1. An axicon comprising a transparent body having a cylindrical outer surface 31, a first light transmitting surface 32, and a second light transmitting surface 35 spaced from said first surface 32; said body being constructed and arranged such that a) if a beam of light 40 is received by the first surface 32 and redirected into the second surface 35, the second surface 35 will transform the beam 40 into a beam 45 different from the received light rays and exiting the end of the body opposite the first surface 32; and b) if ambient light rays are directed onto and received by the second surface 35, the rays will be redirected and transformed by the first surface 32 into a beam 33 exiting the first surface
 32. 2. The axicon defined in claim 1, wherein the outer surface 31 is a right cylinder, and the center of the second surface 35 is coaxial with the body.
 3. The axicon defined in claim 2, wherein the secon surface is conical and a beam exiting the second surface 35 is a planar beam.
 4. The axicon defined in claim 1, wherein the outer surface 31 is a right cylinder, and the center of the second surface 35 is offset from the axis of the body
 5. The axicon defined in claim 2, wherein a beam exiting the second surface 35 defines a plane.
 6. An axicon comprising a light transmissive body having a cylindrical outer surface 31 having first and send ends, a first light transmitting surface 32 at one end of said body, and a second light transmitting surface 35 at the other end of said body from said first surface 32; said body being constructed and arranged such that a beam of light received by the one of said surfaces is redirected to the other of said surfaces, and the other surface will transform the input beam into a exiting beam different from the received light rays and exiting the end of the body at the location of the other surface.
 7. An optical system comprising a pair of cooperating optical members for redirecting light from a plane to a beam and from a beam to a plane, said members each comprising a cylindrical outer surface 15, a conical interior surface 20, and a curved outer lens surface 22, all supported on a common optical axis; said conical interior surfaces being supported to face each other; a pair of photodetectors, one each of which is supported opposite said outer lens surfaces; said system being constructed and arranged such that a) light rays can be received by the cylindrical outer surface 15 and directed into said conical interior surfaces are divided and redirected along the optical axis toward lens surface 22, and each lens surface concentrate and transform the light rays into a beam directed to the associated photodetector; and that b) an input beam can be directed into said lens surface 22 and along the axis of the system to the conical surfaces 20, whereby the light rays of the resultant beam will be redirected and transformed by the conical interior surface into a planar beam exiting the cylindrical outer surface. 